/*
  将下面异步代码使用 Promise 的方法改进
  尽量用看上去像同步代码的方式
  setTimeout(function () {
    var a = 'hello'
    setTimeout(function () {
      var b = 'lagou'
      setTimeout(function () {
        var c = 'I ♥ U'
        console.log(a + b +c)
      }, 10)
    }, 10)
  }, 10)
*/
let a, b, c;
Promise.resolve()
    .then(() => a = 'hello')
    .then(() => b = 'lagou')
    .then(() => {
        c = 'I ♥ U';
        console.log([a, b, c].join(' '));
    });